The early plans for Wrath of the Lich King mention Azjol-Nerub as being a full-fledged questing area; it was originally intended to be the game's first underground zone. At some point, obviously, this changed for some unknown reason that I'm sure was perfectly valid, and the rather ambitious aim of Azjol-Nerub was slightly lowered. Now, it's a five-man dungeon meant for levels 71-74. Scaled down, yes, but still kind of fun.
It's also very, very, quick. After a descent down a twisting path and just a few measly pulls, we were face-to-mandible with the dungeon's first boss, Krik'Thir the Gatewatcher. He has four named guardians with him (each with their own little posse), and the general pace of the encounter feels similar to the General Rajaxx fight back in AQ20. Upon engaging, you fight each of the guards and their companions one group at a time, with the next pack aggroing shortly after the defeat of the one before it. Unfortunately, none of us were really all that familiar with the place, and the pause between waves was juuuuust long enough for us to be thoroughly taken off guard when the next Watcher skittered its way forward.
So we wiped. D'oh.
One soulstone later, and we tried again. This time, we were significantly more successful, and after the fourth wave was done away with, we engaged Krik'Thir himself. ...herself? Itself! 
Looking back on it, I'm actually not entirely sure what exactly Krik'Thir does, because one of its abilities involves summoning a massive swarm of little bugs to attack us. As a Mage, when I see that many red names rushing us, my first (and only) instinct is to start wearing my "2" key to a nub, jumping around and spamming Arcane Explosion and hoping the healer doesn't forget that I'm wearing the Azerothian equivalent of tissue paper for armor.
So, other than periodic bug swarms that need to be dealt with in an AoE fashion, I have no idea what Krik'Thir actually does. Whatever it is, apparently it wasn't very hard because we killed him. Her. It. We killed that big bug thing, all right?
With Krik'Thir the Gatewatcher no longer there to Watch the Gate, we moved further into the dungeon, crossing a large bridge over a massive spider-web. I'm thankful I'm not arachnophobic, because... yeesh. Lots and lots of spiders.
What with the transparent nature of the spider-web floor, we could clearly see below us to the second boss of the dungeon, Hadronox [Spawn of Maexxna]. The lore-nerd in me does a little happy jig at the reference to the big bad from Naxxramas' Spider Wing. 
Perhaps it's just my limited frame of reference, but as far as I'm concerned one big evil spider isn't very different from another big evil spider. So when a bunch of smaller Nerubians start swarming down the spider-web to attack Hadronox, I'm slightly confused. I have no idea why these two forces seem to be at odds, but ... eh, whatever.
As Hadronox fights its way up the spider-web, we too are attacked by even more Nerubians who obviously recognize us as a threat equal to (or greater than) the big evil spider. As before, they come in waves. Also as before, the waves are spaced precisely far apart so that they interrupt you just when you've started to eat and drink. Impolite spider bastards.
After a short while - we've fought three or so waves - Hadronox finishes its casual slaughter of the Nerubian swarm and sets its sights on five tasty morsels. Unfortunately for it, said tasty morsels are PCs and adventurers, so its thorax is toast.
The primary strategy while fighting Hadronox is one we've seen in many, fights before. "Don't stand in the green stuff." Indeed, the green stuff is, er, toxic and if you stand in it? You'll be dead pretty quickly. It's a very mobile fight, and a pretty fun one that I wish I'd paid more attention to instead of focusing on just dodging the green stuff.
The Spawn of Maexxna dies, and he drops a Life-Staff of Something-Or-Other, which has a ton more spellpower than my current level 66 blue, and since nobody else needs it I snatch it right up. Naturally, I can't use it until level 72, but eh, it's nice to have something in the bank. 
